[Analytica Chimica Acta] Microfluidic immunosensor based on mesoporous silica platform and CMK-3/pol
We report a hybrid glass-poly (dimethylsiloxane) microfluidic immunosensor for epidermal growth factor receptor (EGFR) determination, based on the covalent immobilization of anti-EGFR antibody (anti-EGFR) on amino-functionalized mesoporous silica (AMS) retained in the central channel of a microfluidic device. The synthetized AMS was characterized by N2 adsorption-desorption isotherm, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and infrared spectroscopy. The cancer biomarker was quantified in human serum samples by a direct sandwich immunoassay measuring through a horseradish peroxidase-conjugated anti-EGFR. The enzymatic product was detected at −100 mV by amperometry on a sputtering gold electrode, modified with an ordered mesoporous carbon (CMK-3) in a matrix of poly-acrylamide-co-methacrylate of dihydrolipoic acid (poly(AC-co-MDHLA)) through in situ copolymerization. CMK-3/poly(AC-co-MDHLA)/gold was characterized by cyclic voltammetry, EDS and SEM. The measured current was directly proportional to the level of EGFR in human serum samples. The linear range was from 0.01 ng mL−1 to 50 ng mL−1. The detection limit was 3.03 pg mL−1, and the within- and between-assay coefficients of variation were below 5.20%. The microfluidic immunosensor is a very promising device for the diagnosis of several kinds of epithelial origin carcinomas.
Matías Regiart b, Martin A. Fernández-Baldo a, Jhonny Villarroel-Rocha b, Germán A. Messina a, Franco A. Bertolino a, Karim Sapag b, Aaron T. Timperman c, Julio Raba a, a INQUISAL, Departamento de Química, Universidad Nacional de San Luis, CONICET, Chacabuco 917, D5700BWS, San Luis, Argentina b INFAP, Laboratorio de Sólidos Porosos, Universidad Nacional de San Luis, CONICET, Ejercito de los Andes 950, D5700BWS, San Luis, Argentina c Advanced Diagnostics & Therapeutics, Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA Received 10 November 2016, Revised 29 December 2016, Accepted 19 January 2017, Available online 30 January 2017